The invention provides a class of substituted hydroxyl-containing compounds for use in inhibiting specific intra-cellular signaling events often induced by noxious or inflammatory stimuli. More specifically, the inventive compounds have at least one hydroxyl-containing substituent bonded to a core moiety. The inventive compounds are useful antagonists to control intracellular levels of specific non-arachidonyl sn-2 unsaturated phosphatidic acids and corresponding phosphatidic acid-derived diacylglycerols which occur in response to cellular proliferative stimuli.
Pentoxifylline (1-(5-oxohexyl)-3,7-dimethylxanthine), abbreviated PTX and disclosed in U.S. Pat. Nos. 3,422,307 and 3,737,433, is a xanthine derivative which has seen widespread medical use for the increase of blood flow. Metabolites of PTX were summarized in Davis et al., Applied Environment Microbial. 48:327, 1984. One such metabolite, 1-(5-hydroxyhexyl)-3,7-dimethylxanthine, designated M1 and disclosed in U.S. Pat. Nos. 4,515,795 and 4,576,947, increases cerebral blood flow. In addition, U.S. Pat. Nos. 4,833,146 and 5,039,666 disclose use of tertiary alcohol analogs of xanthine for enhancing cerebral blood flow.
U.S. Pat. No. 4,636,507 discloses that PTX and M1 stimulate chemotaxis in polymorphonuclear leukocytes in response to a chemotaxis stimulator. PTX and related tertiary alcohol substituted xanthines inhibit activity of certain cytokines to affect chemotaxis (U.S. Pat. Nos. 4,965,271 and 5,096,906). Administration of PTX and GM-CSF decrease tumor necrosis factor (TNF) levels in patients undergoing allogeneic bone marrow transplant (Bianco et al., Blood 76: Supplement 1 (522A), 1990). Reduction in bone marrow transplant-related complications accompanied reduction in assayable levels of TNF. However, in normal volunteers, TNF levels were higher among PTX recipients. Therefore, elevated levels of TNF are not the primary cause of such complications.
Therefore, effective therapeutic compounds that are safe and effective for human or animal administration and that can maintain cellular homeostasis in the face of a variety of inflammatory stimuli are needed. The invention is a result of research conducted in looking for such compounds.
We have found a genus of compounds useful in a large variety of therapeutic indications for treating or preventing disease mediated by intracellular signaling through one or two specific intracellular signaling pathways. In addition, the inventive compounds and pharmaceutical compositions are suitable for normal routes of therapeutic administration (e.g., parenteral, oral, topical, etc.) for providing effective dosages.
In one of its aspects, the invention includes a method for treating an individual having a disease or treatment-induced toxicity that is characterized by, or can be treated by inhibiting, an immune response or a cellular response to external or in situ primary stimuli, the cellular response being mediated through a specific phospholipid-based second messenger described herein. The second messenger pathway is activated in response to various noxious, proinflammatory or proliferative stimuli characteristic of a variety of disease states. More specifically, the invention includes methods for treating or preventing clinical symptoms of various disease states or reducing toxicity of other treatments by inhibiting cellular signaling through a second messenger pathway involving signaling through a non-arachidonyl phosphatidic acid intermediate. Treatment is carried out by administering an inventive compound, and pharmaceutical compositions thereof, having the formula:
(R)jxe2x80x94(CORE MOIETY),
including resolved enantiomers and/or diastereomers, hydrates, salts, solvates and mixtures thereof, wherein j is an integer from one to three, the core moiety comprises a bicyclic ring structure having at least one heterocyclic ring that contains five to six ring atoms and up to two nitrogen heteroatoms, R is selected from the group consisting of hydrogen, halogen, hydroxyl, amino, substituted or unsubstituted benzyl, C1-6 alkyl or C1-6 alkenyl, preferably the alkyl or alkenyl groups being substituted by an hydroxy, halogen and dimethylamine and/or interrupted by an oxygen atom. Preferred R include, but are not limited to, methyl, ethyl, isopropyl, n-propyl, isobutyl, n-butyl, t-butyl, 2-hydroxyethyl, 3-hydroxypropyl, 3-hydroxy-n-butyl, 2-methoxyethyl, 4-methoxy-n-butyl, 5-hydroxyhexyl, 2-bromopropyl, 3-dimethylaminobutyl, 4-chloropentyl, and the like. Particularly preferred R are ethyl, methyl, or H, and most preferably, methyl or H. At least one R has the formula I: 
wherein n is an integer from 1 to 20, preferably an integer from 3 to 15, more preferably from 6 to 12, and at least one of X or Y is xe2x80x94OH. If only one of X or Y is xe2x80x94OH, then the other X or Y is hydrogen, CH3xe2x80x94, CH3xe2x80x94CH2xe2x80x94, CH3xe2x80x94(CH2)2xe2x80x94, or (CH3)2xe2x80x94CH2xe2x80x94, and W1, W2, and W3 are independently hydrogen, CH3xe2x80x94, CH3xe2x80x94CH2xe2x80x94, CH3xe2x80x94(CH2)2xe2x80x94, or (CH3)2xe2x80x94CH2xe2x80x94, wherein X, Y, W1, W2, and W3 alkyl groups may be substituted by an hydroxyl, halo or dimethylamino group and/or interrupted by an oxygen atom, hydrogen or alkyl (C1-4). Especially preferred compounds have X and Y both being xe2x80x94OH and each of W1, W2, and W3 being hydrogen or methyl. Preferably R having formula I structure is bonded to a ring nitrogen.
Exemplary bicyclic core moieties include, without limitation, substituted or unsubstituted: xanthinyl, dioxotetrahydropteridine, phthalimide, homophthalimide, benzoyleneurea and quinazoline-4(3H)-one. In one preferred embodiment, the core moiety is xanthine or a xanthine derivative.
Especially preferred xanthine compounds have the following formula II: 
wherein R is selected from the foregoing members. Most preferably, a single R having formula I above is bonded to the N1 xanthine nitrogen in formula II or each of two formula I R are bonded to N1 and N7 xanthine nitrogens, respectively. Remaining R substituents are preferably selected from the group consisting of hydrogen, methyl, fluoro, chloro and amino.
The compounds of the present invention are typically used as pharmaceutical compositions combined with a pharmaceutically acceptable excipient. The pharmaceutical composition may be formulated for oral, parenteral, ocular or topical administration to a patient.
In one of its aspects, the invention provides a method for modulating the response of a target cell to a stimulus by contacting the target cell with an effective amount of a compound of the invention. The stimulus is capable of elevating the cellular level of non-arachidonate phosphatidic acid (PA) and diacylglycerol(DAG) derived therefrom, and the compound is provided in an amount that is effective to reduce these elevated levels by an amount that is equal to or greater than that produced by treating the cells with 0.5 mmol pentoxifylline (PTX).
In another of its aspects, the invention provides a method for treating an individual having a disease or treatment-induced toxicity, mediated through a specific phospholipid-based second messenger, by administering a pharmaceutically effective amount of a compound of the invention. The disease is characterized by or can be treated by inhibiting an immune response or cellular response to external or in situ primary stimuli.
The disease or treatment-induced toxicity is selected from the group consisting of: tumor progression involving tumor stimulation of blood supply (angiogenesis) by production of fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF) or platelet-derived growth factor (PDGF); tumor invasion and formation of metastases through adhesion molecule binding, expressed by vascular endothelial cells (VCAM and ICAM); tissue invasion through tumor metalloprotease production such as MMP-9; autoimmune diseases caused by dysregulation of the T cell or B cell immune systems, treatable by suppression of the T cell or B cell responses; acute allergic reactions including, but not limited to, asthma and chronic inflammatory diseases, mediated by pro-inflammatory cytokines including tumor necrosis factor (TNF) and IL-1, and rheumatoid arthritis, osteoarthritis, multiple sclerosis or insulin dependent diabetes mellitus (IDDM), associated with enhanced localization of inflammatory cells and release of inflammatory cytokines and metalloproteases; smooth muscle cell, endothelial cell, fibroblast and other cell type proliferation in response to growth factors, such as PDGF-AA, BB, FGF, EGF, etc. (i.e., atherosclerosis, restenosis, stroke, and coronary artery disease); activation of human immunodeficiency virus infection (AIDS and AIDS related complex); HIV-associated dementia; kidney mesengial cell proliferation in response to IL-1, MIP-1xcex1, PDGF or FGF; inflammation; kidney glomerular or tubular toxicity in response to cyclosporin A or amphotericin B treatment; organ toxicity (e.g., gastrointestinal or pulmonary epithelial) in response to a cytotoxic therapy (e.g., cytotoxic drug or radiation); effects of non-alkylating anti-tumor agents; inflammation in response to inflammatory stimuli (e.g., TNF, IL-1 and the like) characterized by production of metalloproteases or allergies due to degranulation of mast cells and basophils in response to IgE or RANTES; bone diseases caused by overproduction of osteoclast-activating factor (OAF) by osteoclasts; CNS diseases resulting from over-stimulation by proinflammatory neurotransmitters such as , acetylcholine, serotonin, leuenkephalin or glutamate; acute inflammatory diseases such as septic shock, adult respiratory distress syndrome; multi-organ dysfunction associated with inflammatory cytokine cascade; and combinations thereof.
In many cell types, signaling is dependent upon generation of a broad variety of non-arachidonyl PA species, some of which are generated from lyso-PA by the enzyme lyso-PA acyl transferase (LPAAT). Generation of each of these PA species (the predominant forms being: 1-acyl and 1-alkyl 2-linoleoyl PA compounds, generated by LPAAT) serves to effect both proliferative and/or inflammatory signaling in the diseases discussed and cell systems described above.
In yet another aspect, the invention provides a method for treating or preventing acute and chronic inflammatory diseases, AIDS and AIDS related complex, alcoholic hepatitis, allergies due to degranulation of mast cells and basophils, angiogenesis, asthma, atherosclerosis, autoimmune thyroiditis, coronary artery disease, glomerula nephritis, hairloss or baldness, HIV-associated dementia, inflammatory bowel disease, insulin dependent diabetes mellitus, lupus, malignancies, multiple sclerosis, myelogenous leukemia, organ or hematopoietic in response to cytotoxic therapy, osteoarthritis, osteoporosis, peridontal disease, premature labor secondary to uterine infection, psoriasis, restenosis, rheumatoid arthritis, sleep disorders, septic shock, sepsis syndrome, scleroderma, stroke and transplant rejection in a mammal in need of such treatment, comprising administering a pharmaceutically effective amount of a compound of the invention or a pharmaceutical composition thereof.
In yet another aspect, the invention provides a method for inhibiting a cellular process or activity mediated by IL-12 signalling comprising contacting IL-12 responsive cells with an inventive compound, preferably a compound of the invention having a xanthinyl core moiety, and determining that the response of the target cell is thereby modulated.
In still yet another aspect, the present invention provides a method for treating a Th1 cell-mediated inflammatory response in a mammal in need of such treatment, the method comprising administering to the mammal a therapeutically effective amount of an inventive compound having the ability to inhibit an IL-12 mediated cellular process or activity, thereby inhibiting the inflammatory response. The inflammatory response is associated with a disease or condition selected from the group consisting of chronic inflammatory disease, chronic intestinal inflammation, arthritis, psoriasis, asthma and autoimmune disorders (e.g., type-1 IDDM, multiple sclerosis, rheumatoid arthritis, uveitis, inflammatory bowel disease, lupus disorders, and acute and chronic graft-versus-host disease).
The inventive compounds are of particular significance for inhibiting IL-2-induced proliferative responses. IL-2 signaling inhibition is potentially useful in the treatment of numerous disease states involving T-cell activation and hyperproliferation. Exemplary autoimmune diseases are lupus, scleroderma, rheumatoid arthritis, multiple sclerosis, glomerula nephritis, insulin dependent diabetes mellitus (IDDM), as well as potential malignancies, including but not limited to, chronic myelogenous leukemia as well as others.